Conventional liners of EVA or thermoplastic olefins or mixtures thereof usually contain additives such as plasticizers, e.g., mineral oil, which may contribute to contamination of products. Such prior art liners did not offer higher temperature resistances.
In the U.S. Pat. No. 5,306,542 there is disclosed a plastic closure a plastic closure including a base wall having an inner surface, a peripheral skirt extending from the base wall and a liner on the inner surface of the base wall. The liner includes (a) an ethylene vinyl acetate composition, (b) a primary fatty acid amide and (c) a bis-fatty acid amide. Preferably the primary fatty acid amide comprises an oleamide or an erucamide, and the bis-fatty acid amide comprises ethylene-bis-stearamide.
Among the objectives of the present invention are to provide a closure and a liner that can be adhered or preferably compression molded in plastic; and that has specific physical and chemical properties such that the closure and liner can be used for hot fill or autoclaves applications.
In accordance with the invention, the lined plastic closures are capable of withstanding high temperatures which are provided with a liner of a constrained geometry catalyst and polyolefins blended with an amide to provide specific physical and chemical properties, namely, higher temperature resistance, necessary hardness, good process ability.
In accordance with the invention, a plastic closure includes a base wall having an inner surface, a peripheral skirt extending from the base wall and a liner on the inner surface of the base wall.